Comparison of switching diodes, voltage regulator diodes and rectifier diodes

Comparison of switching diodes, voltage regulator diodes and rectifier diodes

The main characteristic of the diode is unidirectional conductivity, that is, under the action of forward voltage, the on-resistance is small; The on-resistance is extremely large or infinite under the action of reverse voltage. Because the diode has the above characteristics, it is often used in the regulation principle of rectifier and regulator diodes in circuits: the characteristic of the regulator diode is that after adding reverse voltage breakdown, the voltage at both ends of it remains basically unchanged. The rectifier diode is damaged after reverse breakdown, so that when the regulator tube is connected to the circuit, if the voltage at various points in the circuit fluctuates due to fluctuations in the power supply voltage or other reasons, the voltage across the load will basically remain unchanged.

Both rectifier diodes and regulator diodes are PN semiconductor devices, but the rectifier diode uses unidirectional conductivity, and the regulator diode uses its reverse characteristics and is connected in the circuit in reverse.

First, switching diode:

The switching diode has a high switching speed, i.e. a high application frequency. switching diodes have good high-frequency performance and are mainly used in switching circuits as electronic switches.

The switching diode has good high-frequency performance and is mainly used in switching circuits as electronic switches, while rectifiers generally have not very good high-frequency performance (rectifiers in switching power supplies also have good high-frequency performance), mainly used for power frequency current rectification. It usually operates in high-voltage and high-current conditions.

Switching diode is a kind of semiconductor diode, which is a type of diode specially designed and manufactured for "on" and "off" on the circuit. It changes from conduction to cut-off or from cut-off to conduction time is shorter than that of general diodes, common 2AK, 2DK and other series, mainly used in electronic computers, pulse and switching circuits.

Second, the regulator diode:

This diode is a semiconductor device with a high resistance until the critical reverse breakdown voltage. At this critical breakdown point, the reverse resistance is reduced to a small value, in this low-impedance region the current increases while the voltage remains constant, and the regulator diode is binned according to the breakdown voltage, because of this feature, the regulator tube is mainly used as a regulator device or voltage reference element.

The characteristic of a regulator diode is that the voltage across it remains largely unchanged until the reverse energization has not broken down. In this way, when the regulator tube is connected to the circuit, if the voltage at various points in the circuit fluctuates due to fluctuations in the power supply voltage or other reasons, the voltage across the load will basically remain unchanged. Regulator diodes are often represented by "ZD" plus numbers in circuits, such as ZD5 for a regulator tube numbered 5.

There are two conditions for the regulator diode to work: 1. The voltage applied to the regulator diode in reverse is greater than the regulator value of the regulator tube. 2. The current passing through the regulator tube should reach its working conditions (that is, the reverse current should be large enough, generally at least a few mA). You take the circuit according to what I said, assuming that it is a 6, 2V regulator tube, the positive pole of the power supply (9V) - resistance (R) - the negative pole of the regulator tube - the positive pole of the regulator tube - the negative pole of the power supply. This resistance should be calculated according to the parameters of the regulator tube, assuming that when the voltage is stabilized, the current is 5mA, then the size of the resistor = (9-6, 2) / 5mA = 1, 4K or so, you can use a 1K resistor. Then you use a multimeter to measure the voltage between the negative electrode and the ground of the regulator tube, which is basically around 6 or 2V, that is, the voltage is stabilized.

Third, rectifier diode:

1. Rectifier diodes are used in the field of power frequency and high current. The general high-frequency performance of the rectifier tube is not very good (the high-frequency performance of the rectifier tube in the switching power supply is also very good), which is mainly used for rectifying the power frequency current. It usually operates in high-voltage and high-current conditions. A rectifier diode is a semiconductor device used to convert alternating current to direct current

2. The working frequency of the rectifier diode is low, and there are voltage and current requirements. The basic characteristic of a diode is unidirectional conductivity. The rectifier diode has a low operating frequency and has voltage and current requirements. There are many types of ordinary diodes, some can be used as rectification, some can be used as detection, limiting, switching, etc., but not necessarily all of them can be used as rectification. However, as long as the requirements of rectification are met in voltage and current, general diodes can be used as rectifiers; However, the rectifier pipe is not necessarily capable of detection, switching and other work.

3. Unidirectional current, when the diode is applied to the forward voltage at the two terminals, the diode is on; When a reverse voltage is applied across the diode, the diode is cut-off. It can be used in circuits such as rectification.